Breakdown of Es ist diese Lüge, die der Nachbar bestreitet.
sein
to be
es
it
dieser
this / that (fem.: diese, neut.: dieses)
der Nachbar
the neighbor (male)
Questions & Answers about Es ist diese Lüge, die der Nachbar bestreitet.
Why is this sentence structured as Es ist diese Lüge, die... instead of just Der Nachbar bestreitet diese Lüge?
This is a cleft sentence (Spaltsatz). By splitting a simple sentence into two parts, you put heavy emphasis on the phrase diese Lüge. It translates exactly to "It is this lie that...", making it crystal clear that the neighbor is denying this specific lie, and not something else.
What case is the relative pronoun die in this sentence?
It is in the accusative case. Even though diese Lüge is in the nominative case in the first half of the sentence, the relative pronoun die acts as the direct object of the verb bestreitet in the second half. The neighbor (der Nachbar, nominative subject) denies the lie (die, accusative object). Since the feminine nominative and accusative forms are both die, it looks the same, but its grammatical function shifts in the relative clause.
If we wanted to say "It is these lies that the neighbor denies", would we still start with Es ist?
No, you would need to say Es sind diese Lügen. In German, when the dummy pronoun es is used with the verb sein (to be) to introduce a noun, the verb conjugates to match the following noun, not the word es. Because Lügen is plural, the verb must become sind.
Could I use leugnen instead of bestreiten here?